多次分段控制注浆斜向预应力钢锚管锚索组合结构加固技术现场试验

Field Test on Reinforcement Technology of Steel Anchor Pipe and Anchor Cable Composite Structure with Multi-stage Control Grouting in Inclined Direction

对多次分段控制注浆斜向预应力钢锚管锚索组合结构新型边坡加固技术的结构形式、适用范围、加固作用机理、现场试验进行分析,对比分析预应力锚索、多次分段控制注浆预应力钢锚管及多次分段控制注浆预应力钢锚管锚索承载力。研究结果表明:①该结构特别适用岩土体破碎、松散、易塌孔地层于边坡,通过钢锚管劈裂注浆,提高边坡岩土体的强度指标,充填了和挤密破碎地层间的空洞和孔隙,有效提高锚固段锚固力。②通过预应力锚索和预应力钢锚管极限承载力对比分析表明预应力钢锚管没能够充分发挥该地层的锚固力。预应力钢锚管施加的预应力只能传到浅表层,且破坏模式为钢管被拉断或者钢管接头处断裂。③三组不同根数的钢绞线预应力钢锚管锚索极限承载力结果与普通的预应力锚索相比来看,单束钢绞线预应力锚索承载力由200 kN增加到235 kN,锚固力提高17.5%;两根钢绞线预应力锚索承载力由295 kN增加到378 kN,锚固力提高28.14%;三根钢绞线预应力锚索承载力由336 kN增加到432.26 kN,锚固力提高28.65%。表明预应力钢锚管锚索通过劈裂注浆挤密锚固段岩土体,浆液充填裂隙,形成“树根状”,有效地提高了锚固段锚固力。

The structural form,applicable scope,reinforcement mechanism and field test of the new slope reinforcement technology of multi-section control grouting oblique prestressed steel anchor pipe anchor cable combination structure were analyzed.And the bearing capacity of prestressed anchor cable,multiple segment control grouting prestressed steel anchor pipe and multi-section control grouting prestressed steel anchor pipe anchor cable was compared and analyzed.The research results show that:①the structure is particularly suitable for rock and soil fracture,loose,easy to collapse formation on the side slope.Through the steel anchor pipe splitting grouting,the strength index of the slope rock and soil body is improved,the voids and pores between the compacted and fractured stratum are filled,and the anchoring force of the anchorage section is effectively improved.②The comparative analysis of the ultimate bearing capacity of prestressed steel anchor pipe shows that the prestressed steel anchor pipe can not fully exert the anchoring force of the formation.The prestressing force applied by the prestressed steel anchor pipe can be transmitted to the superficial layer only,and the failure mode is that the steel pipe is broken or the steel pipe joint is broken.③Compared the ultimate bearing capacity of three sets of steel strand prestressed steel anchor pipe anchor cables with that of the ordinary prestressed anchor cable,the bearing capacity of the single beam steel strand prestressed anchor cable is increased from 200 kN to 235 kN,and the anchoring force is increased by 17.5%.The bearing capacity of the two steel strand prestressed anchor cables is 295 kN.When the load is increased to 378 kN,the anchoring force is increased by 28.14%.The bearing capacity of the three steel strand prestressed anchor cables is increased from 336 kN to 432.26 kN,and the anchoring force is increased by 28.65%.It indicates that the prestressed steel anchor pipe anchor cable compacts the rock mass of the anchorage section by splitting grouting,and the slurry fills the fissure to form a Toot shape,which effectively improves the anchoring force of the anchorage section.